{"id":"18c08ff3-7a7c-533b-be02-3cae66f38a96","stable_key":"0f17db03-207f-5910-ac8e-13dfc2f378ce:mg-nka-distinct-transport-site","predicate":"occupies-site-on","statement":"Mg occupied cation transport site II in the ouabain-bound E2P pig-kidney pump structure.","claim_class":"mechanistic","status":"source_derived_draft","evidence_grade":"ungraded","direction":"context_dependent","is_public":true,"mechanism_event_id":"9159cceb-f69a-50ae-a019-a4b1f591747b","mechanism_event_label":"Magnesium can occupy a membrane ion site distinct from the ATP-associated catalytic site.","subject":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"object":{"id":"27c3e7bd-c6e1-5344-8130-b231a9da2cfb","slug":"sodium-potassium-atpase","display_name":"Sodium-potassium ATPase complexes","entity_type_key":"protein_family"},"evidence_count":1,"mechanism_event":{"id":"9159cceb-f69a-50ae-a019-a4b1f591747b","stable_key":"0f17db03-207f-5910-ac8e-13dfc2f378ce:mg-nka-distinct-transport-site-event","event_type":"biochemical_relationship","label":"Magnesium can occupy a membrane ion site distinct from the ATP-associated catalytic site.","description":"Mg occupied cation transport site II in the ouabain-bound E2P pig-kidney pump structure.","status":"provisional","compartment":null,"participants":[{"entity":{"id":"5dd31e52-f51e-51f3-880e-240abcc0ab1d","slug":"potassium-ion","display_name":"Potassium ion","entity_type_key":"ion"},"role":"competing ion at the transport site","stoichiometry":null,"state_label":"","sequence_order":0,"notes":""},{"entity":{"id":"24904faf-f4b4-5e5a-a2e6-3549fb7a2a2e","slug":"mg-atp","display_name":"Magnesium-ATP complex","entity_type_key":"chemical_species"},"role":"distinct catalytic chemical species","stoichiometry":null,"state_label":"","sequence_order":1,"notes":""},{"entity":{"id":"bff427ab-35f9-59c2-bb24-fd5953bbaec2","slug":"magnesium-ion","display_name":"Mg2+","entity_type_key":"ion"},"role":"subject","stoichiometry":null,"state_label":"","sequence_order":2,"notes":""},{"entity":{"id":"27c3e7bd-c6e1-5344-8130-b231a9da2cfb","slug":"sodium-potassium-atpase","display_name":"Sodium-potassium ATPase complexes","entity_type_key":"protein_family"},"role":"target","stoichiometry":null,"state_label":"","sequence_order":3,"notes":""}]},"contexts":[{"dimension":"cross_nutrient","value_text":"Magnesium-dependent ATP chemistry is coupled to sodium and potassium handling by the pump; serum magnesium is not the enzyme-site concentration.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"experimental_model","value_text":"Phosphorylated pig-kidney Na/K-ATPase-ouabain complex crystallography.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"limitations","value_text":"Drug-stabilized inhibited state; it does not demonstrate physiological Mg transport.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"nutrient_topic","value_text":"Magnesium research collection; topical membership is not evidence of a direct dietary effect.","comparator":null,"unit":null,"notes":"","entity":{"slug":"magnesium","display_name":"Magnesium","entity_type_key":"nutrient_element"}},{"dimension":"organism","value_text":"Sus scrofa","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"plain_language","value_text":"Magnesium can occupy a membrane ion site distinct from the ATP-associated catalytic site.","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"primary_references","value_text":"[laursen-2013-nka] Crystal structure of the high-affinity Na+K+-ATPase-ouabain complex with Mg2+ bound in the cation binding site (2013). https://pubmed.ncbi.nlm.nih.gov/23776223/ DOI: 10.1073/pnas.1222308110","comparator":null,"unit":null,"notes":"","entity":null},{"dimension":"tissue_or_cell_type","value_text":"Kidney enzyme crystals","comparator":null,"unit":null,"notes":"","entity":null}],"evidence":[{"id":"4f096944-4511-5463-a217-699d9ea2ceaa","evidence_kind":"source_excerpt","locator":"Lines 845-855","start_line":845,"end_line":855,"excerpt":"### mg-nka-distinct-transport-site\nMg occupied cation transport site II in the ouabain-bound E2P pig-kidney pump structure.\nCondition category: normal\nnutrient_topic: Magnesium research collection; topical membership is not evidence of a direct dietary effect.\nplain_language: Magnesium can occupy a membrane ion site distinct from the ATP-associated catalytic site.\norganism: Sus scrofa\ntissue_or_cell_type: Kidney enzyme crystals\nexperimental_model: Phosphorylated pig-kidney Na/K-ATPase-ouabain complex crystallography.\nlimitations: Drug-stabilized inhibited state; it does not demonstrate physiological Mg transport.\ncross_nutrient: Magnesium-dependent ATP chemistry is coupled to sodium and potassium handling by the pump; serum magnesium is not the enzyme-site concentration.\n[laursen-2013-nka] Crystal structure of the high-affinity Na+K+-ATPase-ouabain complex with Mg2+ bound in the cation binding site (2013). https://pubmed.ncbi.nlm.nih.gov/23776223/ DOI: 10.1073/pnas.1222308110","model_system":"Phosphorylated pig-kidney Na/K-ATPase-ouabain complex crystallography.","directness":"author_interpretation","verification_status":"source_derived_draft","notes":"Exact curation-document quotation, not publisher quotation. Study references: [laursen-2013-nka] Crystal structure of the high-affinity Na+K+-ATPase-ouabain complex with Mg2+ bound in the cation binding site (2013). https://pubmed.ncbi.nlm.nih.gov/23776223/ DOI: 10.1073/pnas.1222308110","relationship":"supports","weight":1.0,"link_notes":"","source":{"id":"dd101e28-1a2e-5a48-9d1e-809c77514866","stable_key":"import-0f17db03-207f-5910-ac8e-13dfc2f378ce","title":"Magnesium: cross-nutrient mechanisms and deficiency (2026-09-17)","document_type":"imported_text","citation_label":"AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text.","file_path":"","sha256":"e111c412f57143a17e8e65e74e8f7888b5bb9a61099873f4767f527fac19bb07","revision_id":"6b7f04f2-66ed-5859-955f-c2b50d4bf041","review_status":"unverified_draft","notes":""}}],"relations":[],"conflicts":[],"corrections":[],"research":null}